A busway and bikeway across Manhattan streets will be part of a larger plan to mitigate the disruption caused by the looming L train shutdown.

The highly-anticipated plan, unveiled Wednesday, will also include increased subway service along lines near the L train; the establishment of high-occupancy vehicle restrictions over the Williamsburg Bridge; a new bus network and a strategy to improve subway access that includes reopening several closed station entrances in Brooklyn.

Both the city’s Department of Transportation and MTA aim for the new measures to adequately absorb the 225,000 daily commuters who travel between Manhattan and Brooklyn through the L train’s Canarsie tunnel.

“The proposal . . . is a joint effort looking at everything we heard from the community and being able to respond to those community needs,” said MTA chairman Joe Lhota. “We’re doing it from a point of view that . . . it’s not just Williamsburg, it’s all the way down from where the line begins in Canarsie.”

The agencies hope the plan will quell the apocalyptic fears of residents, workers and business owners in Brooklyn who have worried for more than a year about the implications for traffic and commerce in what will be the MTA’s most substantial service outage in history.

The 100-year-old Canarsie tunnel under the East River will close for 15 months beginning in April 2019, shuttering L train service to and through Manhattan so that the MTA can make badly needed repairs to infrastructure flooded with seven million gallons of saltwater during superstorm Sandy in 2012.

To help move commuters across Manhattan, the agencies will build a busway over a portion of 14th Street, between Third and Ninth avenues, and close vehicular access to the stretch of roadway during morning and evening rush hours.

Only local deliveries will be permitted, giving the city space to create one travel lane for buses in each direction, as well as one lane dedicated for bus stops and another two lanes dedicated to providing additional pedestrian space. During peak hours, this will allow the MTA to run a bus about every minute with off-board fare collection.

“The challenge we face in Manhattan on 14th Street is taking those 50,000 L train subway riders who are Manhattan-only . . . and basically accommodating them on the surface,” said city Department of Transportation Commissioner Polly Trottenberg. “So we’re proposing a pretty bold re-envisioning of 14th Street.”

The bikeway will be built on 13th Street and entails installing a green-painted, two-way bike lane that is buffered by another painted zone, creating what will be Manhattan’s first fully protected, east-west bike lane.

Both the MTA and DOT plan to hold a round of public input sessions on their plan, which still could be tweaked. The agencies’ strategy outlines that they’re still looking to make “major changes” to Grand Street in Brooklyn, an important artery leading to the Williamsburg Bridge.

“There are lot of important businesses and it’s a truck route and it’s a pretty narrow street,” said Trottenberg. “Something we’re still working through is how we are going to best accommodate all those uses on the Williamsburg side, but obviously a lot of focus will be on the redesigning of Grand Street.”

There will also be more pedestrian-focused areas around Union Square. Union Square West, from 14th to 15th streets and 16th to 17th streets, will get “new pedestrian space,” according to the plan. And University Place, from 13th to 14th streets, will completely close to vehicular traffic.

Subways

The MTA anticipates that the majority of displaced L train commuters — about 80 percent — will switch to nearby subway lines. It will increase service on the J, M and Z lines and run full-length trains on the G. J and Z trains will run local between the Myrtle Avenue and Marcy Avenue stations in order to help serve the packs of riders anticipated at the Hewes Street, Lorimer Street and Flushing Avenue stations. It will also provide free MetroCard transfers at several points.

“We know we have to improve some of the capacity of some of the stations where these riders will be going,” said Ronnie Hakim, the MTA’s managing director, adding that the agency is “really trying to utilize this shutdown as an opportunity to get as much work as we can get done within the 15-month time frame.”

Closed station entrances will reopen for the Metropolitan Avenue stop of the G train, at Powers Street, and at the Hewes Street station as well. Hakim said that the recently reopened entrance of the Flushing Avenue station of the J, M and Z trains, at Fayette Street, will help as well.

The MTA will also undertake a variety of projects to improve the flow of passengers at six key subway stations: Marcy Avenue, Lorimer Street, Broadway Junction, Court Square, Nassau Avenue and Metropolitan Avenue-Lorimer Street. The projects involve widening or building new stairs or improving turnstile areas.

Elevators and additional stairs will be installed at the First Avenue and Bedford Avenue stations and the Union Square station will receive to-be-detailed capacity improvements as well.

Buses and Ferries

Over the East River, the agencies are looking at the Williamsburg Bridge to shoulder the load of commuters. Each lane on the bridge will be accessible only to trucks and vehicles with three or more passengers during morning and evening rush hours in order to keep the bridge clear for the additional bus service that will be shuttling riders between boroughs. The agencies expect the changes will help carry 3,800 bus riders on 70 buses during an average peak hour.

“It’s no secret that we need to do something pretty dramatic both on the bridge itself and on the approaches on the Brooklyn and Manhattan sides to make sure these buses can process at a regular rate,” said Trottenberg.

There will be at least three new bus routes that will be put in place to move commuters between boroughs via the Williamsburg Bridge. Each route has specific pick-up and drop-off points near functioning subway stations.

One route will carry riders from the Grand Street station of the L train to the First Avenue station at 15th Street in Manhattan, with one stop at the Delancey Street-Essex Street station of the F, M, J and Z trains.

Another route will also pick up riders from the Grand Street station, making a loop in SoHo with a stop at Delancey Street-Essex Street; another between the Spring Street and Prince Street stations and a third by the Bleecker Street/Broadway–Lafayette Street station.

A third route will pick up riders around a loop near the Bedford Avenue station, making identical stops along the SoHo route.

The MTA will also run a new ferry route on the East River, connecting North Williamsburg to Stuyvesant Cove, dropping off riders near the 14th Street bus service.

Response

A variety of planning firms and advocacy groups had pitched the MTA and DOT all sorts of ideas to get people around the L outage, including 24-hour closures of vehicular traffic on 14th and Grand streets in order to bolster bus service.

What was unveiled Wednesday fell short of those bigger ideas. Joe Cutrufo, a spokesman for Transportation Alternatives, said there is room for improvement.

“We’re pleased to see the City and the MTA working together on a plan that addresses the L train corridor on both sides of the East River,” Cutrufo said in a statement. “Certainly there are some areas where we’d like to see changes, but this is a strong first step.”

Brooklyn Councilman Antonio Reynoso said he would press DOT and MTA officials for more ideas in his borough at a City Council oversight hearing on the L train shutdown scheduled for Thursday morning.

“It seems the administration forgot about moving traffic or adding alternatives in Brooklyn,” Reynoso tweeted. “We will not be the stepchild of this plan.”